The present invention relates to clamping elements or fixtures with a short clamping stroke, designed to exert a clamping or other holding force on a workpiece and having an internal cavity to be supplied with driving fluid, more particularly compressed air.
If a workpiece is to be machined it has to be placed on the work table of the machine tool or other manufacturing device and clamped in place to keep it from changing its position in the course of the machining operation that is to take place, as for example the production of a hole. It is more particularly in mass-production of workpieces that clamping fixtures, that are permanently mounted on the machine, are used in the form of clamping cylinders whose plungers are moved outwards when fed with driving fluid to press the work against a counter abutment. In this respect the number of clamping cylinders depends on the dimensions of the respective workpiece. If the workpiece has a large surface area, it will be necessary to use a number of clamping cylinders spaced out from each other in a row along the workpiece.
However such an arrangement with a series of clamping cylinders uses a large amount of material and is comparatively expensive. Furthermore on tooling up the machine the clamping cylinders have to be individually set in place so that the tooling process is slowed down. A further point is that the clamping cylinders engage the work at a limited number of separate points so that there is a high specific pressure exerted at such positions if the clamping force is to be high enough. This may result in damage to the work, as for example in the case of wooden structures that are then prove to have been dented by the impression of the piston plungers.